:# Ambush (v), to attack someone or something from a hidden or unexpected position.
# Lurk (v) to remain hidden or concealed, often in a sneaky or stealthy manner, waiting for an opportunity to attack or surprise someone or something.
# Waylay (v), to attack or seize someone or something from a hidden or unexpected position, often in a surprise or ambush-like manner.
# Set a trap
This phrase means to prepare a hidden or concealed danger or surprise, often with the intention of catching or attacking someone or something.